CN211521950U - System for reducing concentration of pollutants in steel comprehensive wastewater - Google Patents

Abstract

The utility model relates to a system for reducing the pollutant concentration of iron and steel comprehensive wastewater, comprising a regulating tank, a high-density sedimentation tank, a biological aeration filter, a denitrification biological filter, a high-efficiency dissolved air flotation tank, a filter tank and a A pool and an ozone catalytic oxidation pool; the utility model can completely convert the pollutants in the waste water into non-pollutant substances, achieve the purpose of reducing the concentration of pollutants, and meet the requirements for water pollution in Table 3 of the "Iron and Steel Industry Water Pollutant Discharge Standard GB13456-2012" The requirements of the special discharge limit of pollutants, and fully meet the water quality indicators of the double-membrane desalination and reuse in order to improve the service life of the desalination and reuse facilities.

Description

A system for reducing the concentration of pollutants in iron and steel comprehensive wastewater

technical field

The utility model relates to the technical field of industrial wastewater treatment, in particular to a system for reducing the pollutant concentration of iron and steel comprehensive wastewater.

Background technique

Iron and steel enterprises are major water users, producing a large amount of production wastewater. The indicators of SS, COD, ammonia nitrogen, total nitrogen, fluoride, cyanide and other indicators in the wastewater are easy to exceed the standard and cannot be directly discharged. The use of desalination and reuse of industrial wastewater is the development trend of the industry, but this method does not remove pollutants, but transfers the pollutants to concentrated brine, and the reuse of concentrated brine will inevitably cause secondary pollution. In addition, the double-membrane method for desalination has strict requirements on the influent water, and the quality of the influent water is good, which can greatly improve the service life of the desalination equipment. Therefore, it is best to reduce the concentration of pollutants before the wastewater enters the double-membrane desalination system.

SUMMARY OF THE INVENTION

The utility model provides a system for reducing the concentration of pollutants in comprehensive iron and steel wastewater, which can completely convert the pollutants in the wastewater into non-pollutant substances, achieve the purpose of reducing the concentration of pollutants, and meet the requirements of the "Water Pollutant Discharge Standard for Iron and Steel Industry GB13456- 2012 "Table 3 of the special discharge limit requirements for water pollutants, and fully meet the double-membrane desalination and reuse influent water quality indicators to improve the service life of desalination and reuse facilities.

In order to achieve the above object, the utility model adopts the following technical solutions to realize:

A system for reducing the concentration of pollutants in iron and steel comprehensive wastewater, including a regulating tank, a high-density sedimentation tank, a biological aeration filter, a biological denitrification filter, a high-efficiency dissolved air flotation tank, a filter tank and an ozone catalysis tank connected in sequence through a wastewater pipeline oxidation pool; where:

A liftable aerator is arranged in the regulating tank;

The high-density sedimentation tank is provided with a drug dosing device, and the high-density sedimentation tank is provided with a sediment discharge port connected to the sludge treatment system through a pipeline;

The aeration biological filter is provided with a fixed aerator, and the fixed aerator is connected to the air suspension fan through a pipeline;

The denitrification biological filter is provided with an inert gas inlet and a carbon source dosing device; the denitrification biological filter is provided with a water inlet at the bottom and a water outlet at the upper part, and at least two layers of filter layers are arranged in the tank body, including a filter layer arranged in the lower layer. Oxygen bacteria inhibition layer and denitrification layer arranged on the upper layer;

The waste water pipeline upstream of the high-efficiency dissolved air flotation tank is provided with a tubular reactor, and the tubular reactor is provided with a phosphorus removal agent addition port and a flocculant addition port; the high-efficiency dissolved air flotation tank is divided into water inlet area, In the water distribution area and separation area, the water inlet of the water inlet area is connected with the water outlet of the tubular reactor, and the air flotation device is installed in the water inlet area; the top of the water distribution area is equipped with a slag scraper, and the lower part of the water distribution area is equipped with a corrugated inclined plate , the bottom is provided with a mud discharge port; the bottom of the separation zone is provided with a mud scraper and an automatic mud discharge valve; There is an automatic mud valve on it.

A heating device is also provided in the conditioning tank, and the heating device is an electric heating device or a steam heating device.

The drug dosing device in the high-density sedimentation tank is one of lime dosing device, calcium chloride dosing device, sodium carbonate dosing device, sodium bicarbonate dosing device, PAC dosing device and PAM dosing device. one or more.

The air suspension fan adopts frequency conversion control.

The air flotation device is composed of a dissolved air tank, a circulating pump and a releaser. The dissolved air tank is provided with an air inlet, a circulating water inlet and a dissolved air water outlet. The circulating water inlet and the circulating water outlet on the water inlet area pass through the circulating water pipeline. The circulating water pipeline is provided with a circulating pump, and the dissolved air water outlet is connected with the releaser in the water inlet area.

The filter tank is a sand filter tank or a V-type filter tank.

A backwash water outlet is set on the waste water pipeline downstream of the filter tank, and the backwash water inlet of the aeration biological filter tank, the denitrification biological filter tank and the filter tank are respectively connected through the backwash water pipeline; The biological filter tank and the filter tank are respectively provided with a backwash drain outlet, which is connected to the adjustment tank through a backwash drain pipe.

Compared with the prior art, the beneficial effects of the present utility model are:

1) The process and system settings are reasonable, which can adapt to the comprehensive iron and steel wastewater quality, and can simultaneously remove SS, COD, ammonia nitrogen, total nitrogen, fluoride, hardness, turbidity, chroma, total iron, oil and other pollutants in the wastewater.

2) The treated wastewater can meet the requirements of the special discharge limit index of water pollutants in Table 3 of "Water Pollutant Discharge Standard for Iron and Steel Industry GB13456-2012", and can be used as a pretreatment process for double-membrane desalination;

3) The removal rate of pollutants in wastewater is greatly improved, among which the removal rate of ammonia nitrogen can reach more than 95%, the removal rate of COD can reach more than 90%, and the removal rate of total nitrogen can reach more than 90%.

Description of drawings

FIG. 1 is a schematic structural diagram of a system for reducing the concentration of pollutants in comprehensive iron and steel wastewater according to the present invention.

Detailed ways

The specific embodiments of the present utility model will be further described below in conjunction with the accompanying drawings:

As shown in Figure 1, a system for reducing the pollutant concentration of comprehensive iron and steel wastewater according to the present utility model comprises a regulating tank, a high-density sedimentation tank, a biological aerated filter tank, a biological denitrification filter tank, High-efficiency dissolved air flotation tank, filter tank and ozone catalytic oxidation tank; of which:

A liftable aerator is arranged in the regulating tank;

The high-density sedimentation tank is provided with a drug dosing device, and the high-density sedimentation tank is provided with a sediment discharge port connected to the sludge treatment system through a pipeline;

The aeration biological filter is provided with a fixed aerator, and the fixed aerator is connected to the air suspension fan through a pipeline;

The denitrification biological filter is provided with an inert gas inlet and a carbon source dosing device; the denitrification biological filter is provided with a water inlet at the bottom and a water outlet at the upper part, and at least two layers of filter layers are arranged in the tank body, including a filter layer arranged in the lower layer. Oxygen bacteria inhibition layer and denitrification layer arranged on the upper layer;

The waste water pipeline upstream of the high-efficiency dissolved air flotation tank is provided with a tubular reactor, and the tubular reactor is provided with a phosphorus removal agent addition port and a flocculant addition port; the high-efficiency dissolved air flotation tank is divided into water inlet area, In the water distribution area and separation area, the water inlet of the water inlet area is connected with the water outlet of the tubular reactor, and the air flotation device is installed in the water inlet area; the top of the water distribution area is equipped with a slag scraper, and the lower part of the water distribution area is equipped with a corrugated inclined plate , the bottom is provided with a mud discharge port; the bottom of the separation zone is provided with a mud scraper and an automatic mud discharge valve; There is an automatic mud valve on it.

A heating device is also provided in the conditioning tank, and the heating device is an electric heating device or a steam heating device.

The drug dosing device in the high-density sedimentation tank is one of lime dosing device, calcium chloride dosing device, sodium carbonate dosing device, sodium bicarbonate dosing device, PAC dosing device and PAM dosing device. one or more.

The air suspension fan adopts frequency conversion control.

The air flotation device is composed of a dissolved air tank, a circulating pump and a releaser. The dissolved air tank is provided with an air inlet, a circulating water inlet and a dissolved air water outlet. The circulating water inlet and the circulating water outlet on the water inlet area pass through the circulating water pipeline. A circulating pump is installed on the circulating water pipeline, and the dissolved gas water outlet is connected with the releaser in the water inlet area.

The filter tank is a sand filter tank or a V-type filter tank.

A backwash water outlet is set on the waste water pipeline downstream of the filter tank, and the backwash water inlet of the aeration biological filter tank, the denitrification biological filter tank and the filter tank are respectively connected through the backwash water pipeline; The biological filter tank and the filter tank are respectively provided with a backwash drain outlet, which is connected to the adjustment tank through a backwash drain pipe.

The technological process of the system for reducing the pollutant concentration of iron and steel comprehensive wastewater according to the present invention is as follows:

1) The comprehensive iron and steel wastewater first enters the regulating tank, which is used to adjust the water volume, balance the water quality, and prevent sludge precipitation; oxygenate the wastewater through aeration, and oxidize the ferrous iron in the wastewater to ferric iron, so that it can be used in the follow-up. In the high-density sedimentation tank, the total iron is removed by adding lime to form ferric hydroxide precipitation to meet the requirements of wastewater desalination and reuse; in the regulating tank, the wastewater is heated as needed to avoid the effect of subsequent biochemical treatment due to low water temperature. Double-membrane desalination water production rate;

2) The effluent from the adjustment tank enters the high-density sedimentation tank; in the high-density sedimentation tank, it is necessary to add drugs according to the water quality of the wastewater, including adding lime to remove hardness to meet the requirements of wastewater desalination and reuse; adding lime and calcium chloride Remove fluoride to meet the standard requirements of fluoride in effluent; add sodium carbonate or sodium bicarbonate to supplement the alkalinity to meet the alkalinity required for the ammoniation reaction and the alkalinity requirements for subsequent ammonia nitrogen removal; add PAC and PAM to form flocs , to remove SS; the sludge produced by the high-density sedimentation tank enters the sludge treatment system for treatment;

3) The effluent from the high-density sedimentation tank enters the biological aerated filter; the COD in the wastewater is removed in the biological aerated filter, and ammonia nitrogen is converted into nitrate;

4) The effluent from the aerated biological filter enters the denitrification biological filter; the denitrification biological filter adopts the upper effluent method, and the wastewater first passes through the aerobic bacteria inhibition layer to reduce DO, and then passes through the denitrification layer; when the wastewater passes through the denitrification layer, the other The carbon source is an electron donor to undergo denitrification reaction, and the nitrate is converted into nitrogen and discharged; the function of adding an inert gas is to expand the filter material, and the biologically-generated aging sludge flows out along the water flow;

5) The effluent of the denitrification biological filter enters the high-efficiency dissolved air flotation tank; the waste water first enters the tubular reactor, and the phosphorus removal agent and flocculant are added to the tubular reactor to make the impurities in the waste water form separable flocs; waste water After entering the water inlet area, the flocs come into contact with the air bubbles with a diameter of 30-50um released from the dissolved gas water to form a low-density "air flotation body", while removing oil and suspended solids in the wastewater, and the flocs coalesce in the water distribution area. It is scum, which is scraped to the slag collection tank by the slag scraper, and then discharged into the sludge treatment system; the flocs with a slower rising speed and water flow downward through the corrugated inclined plate to further coalesce, and the low-density flocs float up to the sludge. On the water surface, the high-density flocs settle to the bottom, and the sand deposited in the water distribution area is discharged through the sand discharge port; the sediment deposited in the water inlet area and the sludge deposited at the bottom of the separation area are scraped by the scraper to the sludge discharge end, and passed through the discharge port. The automatic sludge discharge valve is regularly and quantitatively discharged into the sludge treatment system;

6) The effluent from the high-efficiency dissolved air flotation tank enters the filter tank to remove suspended solids and reduce turbidity;

7) The effluent from the filter tank enters the ozone catalytic oxidation tank, part of the COD in the wastewater is degraded in the high-density sedimentation tank and aerated biological filtration, and the remaining part is removed in the ozone catalytic oxidation tank; The BOD reaches the standard, and the COD of the system effluent is less than or equal to 30mg/L.

The utility model is used as the pretreatment process of the double-membrane desalination process, and the effluent of the system enters the double-membrane desalination system, and step 5) is omitted at this time, or the effluent of the denitrification biological filter is directly sent to the subsequent treatment device through the surpassing pipeline.

The aeration biological filter adopts air suspension fan aeration, and performs frequency conversion control according to the effluent DO situation, saving power consumption.

The denitrification biological filter adopts an inert gas to drive out DO to improve the denitrification effect; and an external carbon source is used to carry out the denitrification reaction. The filter material that inhibits the growth of bacteria is arranged in the lower layer, and the added carbon source will not be consumed due to the growth of aerobic bacteria, saving about one third of the carbon source. Using the upper effluent method, the wastewater passes through the denitrification layer, and the carbon source is used as the electron donor to undergo a denitrification reaction, and the nitrate is converted into nitrogen and discharged. At the same time, due to the entry of inert gas, the filter material expands, and the biologically-generated aging sludge flows out along the water flow, reducing the probability of filter material blockage and prolonging the backwash cycle. If the effluent of the system enters the double-membrane desalination system, the process of denitrification biological filter can be canceled or the setting can be overridden by overtaking the pipeline.

The high-efficiency dissolved air flotation tank is used to remove the difficult-to-settlement biological sludge produced by the denitrification process, and reduce the subsequent filtration pressure; remove the oil in the wastewater, protect the subsequent double-membrane desalination system, and prevent the oil from causing membrane fouling. Since the biological sludge contains air bubbles, it is difficult to settle. The incoming water first enters the tubular reactor, and the flocculation agent is added to the tubular reactor to form separable flocs. After mixing with part of the dissolved gas water, the flocs are coalesced. , dense. The sediment deposited in the water inlet area and the sludge deposited at the bottom of the separation area are scraped by the scraper to the sludge discharge end, and discharged into the sludge system regularly and quantitatively through the automatic sludge discharge valve, which does not affect the normal operation of the equipment.

The air flotation device uses air as the air source, which is mixed with the water pressurized by the circulating pump in the dissolved air tank to form dissolved air water, which is released to the water inlet chamber through the releaser. It can remove oil and suspended solids in wastewater at the same time, protect the water quality of the subsequent double-membrane demineralization, and prolong the filter backwash cycle.

The ozone catalytic oxidation tank plays the role of reducing the COD and chromaticity of the effluent. Part of the COD in the wastewater is degraded in the high-density sedimentation tank and aerated biological filter, and the remaining part is removed in the ozone catalytic oxidation tank; in order to achieve a higher removal effect by denitrification, prevent excessive or incomplete addition of carbon sources. Biological utilization, through the ozone catalytic oxidation tank can play a role in ensuring that the effluent COD and BOD does not exceed the standard.

The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited to this. Equivalent replacement or modification of the new technical solution and its utility model concept shall be included within the protection scope of the present utility model.

Claims (7)

1. a system that reduces the pollutant concentration of iron and steel comprehensive waste water, is characterized in that, comprises regulating tank, high-density sedimentation tank, aerated biological filter tank, denitrification biological filter tank, high-efficiency dissolved air flotation tank connected successively by waste water pipeline , filter and ozone catalytic oxidation tank; of which: A liftable aerator is arranged in the regulating tank; The high-density sedimentation tank is provided with a drug dosing device, and the high-density sedimentation tank is provided with a sediment discharge port connected to the sludge treatment system through a pipeline; The aeration biological filter is provided with a fixed aerator, and the fixed aerator is connected to the air suspension fan through a pipeline; The denitrification biological filter is provided with an inert gas inlet and a carbon source dosing device; the denitrification biological filter is provided with a water inlet at the bottom and a water outlet at the upper part, and at least two layers of filter layers are arranged in the tank body, including a filter layer arranged in the lower layer. Oxygen bacteria inhibition layer and denitrification layer arranged on the upper layer; The waste water pipeline upstream of the high-efficiency dissolved air flotation tank is provided with a tubular reactor, and the tubular reactor is provided with a phosphorus removal agent addition port and a flocculant addition port; the high-efficiency dissolved air flotation tank is divided into water inlet area, In the water distribution area and separation area, the water inlet of the water inlet area is connected with the water outlet of the tubular reactor, and the air flotation device is installed in the water inlet area; the top of the water distribution area is equipped with a slag scraper, and the lower part of the water distribution area is equipped with a corrugated inclined plate , the bottom is provided with a mud discharge port; the bottom of the separation zone is provided with a mud scraper and an automatic mud discharge valve; There is an automatic mud valve on it. 2 . The system for reducing the pollutant concentration of comprehensive iron and steel wastewater according to claim 1 , wherein a heating device is also provided in the regulating tank, and the heating device is an electric heating device or a steam heating device. 3 . 3. a kind of system that reduces the pollutant concentration of iron and steel comprehensive wastewater according to claim 1, is characterized in that, the medicine dosing device in described high-density sedimentation tank is lime dosing device, calcium chloride dosing device, One or more of sodium carbonate dosing device, sodium bicarbonate dosing device, PAC dosing device and PAM dosing device. 4 . The system for reducing the pollutant concentration of comprehensive iron and steel wastewater according to claim 1 , wherein the air suspension fan adopts frequency conversion control. 5 . 5. The system for reducing the pollutant concentration of comprehensive iron and steel wastewater according to claim 1, wherein the air flotation device is composed of a dissolved air tank, a circulating pump and a releaser, and the dissolved air tank is provided with an air inlet, The circulating water inlet and the dissolved gas water outlet are connected with the circulating water outlet on the water inlet area through the circulating water pipeline, the circulating water pipeline is equipped with a circulating pump, and the dissolved gas water outlet is connected with the releaser in the water inlet area. 6 . The system for reducing the pollutant concentration of comprehensive iron and steel wastewater according to claim 1 , wherein the filter tank is a sand filter tank or a V-shaped filter tank. 7 . 7. The system for reducing the pollutant concentration of comprehensive iron and steel wastewater according to claim 1, wherein a backwash water outlet is provided on the wastewater pipeline downstream of the filter tank, and the aeration organisms are respectively connected through the backwash water pipeline. The filter, denitrification biological filter and the backwash water inlet of the filter; the aeration biological filter, the denitrification biological filter and the filter are respectively provided with backwash drains, which are connected to the adjustment tank through the backwash drain pipeline.

Images